EFA, Essential Fatty Acids are an important nutritional topic and hopefully this will help cut through the confusion and the myths. Here we go!

What makes it essential?

There are many fatty acids that the mammalian body uses in virtually every cell in the body. The EFA, Essential Fatty Acids are the fatty acids which cannot be made by the body but which must be obtained through diet.
Lets breakdown the types of Fatty acids.

There are two main groups of EFAs: Omega 3 FA and Omega 6 FA. Their name comes from the placement of a double bond between carbon molecules. Omega threes have the final double bond at n-3 and Omega 6’s have them at n-6. Thus they are often referred to as n-3 FA and n-6 FAs. ( Don’t worry, I won’t bore you with going into any more detail of the biochemistry of it all).

Omega 6 – Beware of too much of these…

Omega 6 is plentiful and easy to find in many foods including: canola oil (rapeseed), most vegetable oils, eggs, cereals, safflower oil, sunflower oil, nuts, whole grain breads, poultry, baked goods, etc… While Omega 6 FA are necessary for life, too much of a good thing is a bad thing! n-6 FA’s are responsible for precursors to inflammation. One of the most important n-6’s is Arachidonic Acid. (no it isn’t spider acid but for the many bad things it can do – it might as well be!). To be fair, we need arachidonic acid to live in so much as we need inflammation as part of our immune system. Arachidonic acid it is responsible for the Arachidonic Cascade which produces the hormones of inflammation such as leukotrienes, prostaglandins and many more. While many animals can convert other forms of n-6 FA into the Arachidonic acid (also a n-6 FA), many obligate carnivores (like our beloved house cat) cannot easily make this transition. Thus they can obtain what they need from a meat based diet. One study involving feeding arachidonic acid to mice suggests a possible link to Alzheimer's disease. (not so fun to forget where your cheese is!) What else does too much n-6s do? Well they interfere with the wonderful effects of n-3 FAs by using the same enzymes that n-3 FA’s use to do their job (this is called competitive inhibition for other geeks like me out there who might be reading this.) Furthermore “excessive production of n−6 eicosanoids is associated with heart attacks, thrombotic stroke, arrhythmia, arthritis, osteoporosis, inflammation, mood disorders and cancer” (Calder, Philip C. (June 2006). "n−3 polyunsaturated fatty acids, inflammation, and inflammatory diseases". American Journal of Clinical Nutrition (American Society for Nutrition) 83 (6, supplement): 1505S–1519S).

Ratio of Omega 6 to 3

So what do we do? Not eat the myriad of food that has n-6? And if we don’t eat any we die? Is this hopeless?? Not at all. The key lies in the ratio of omega 6 to omega 3. The Greeks ‘Golden Mean’.

The proper or ideal ratio is typically thought to be 5:1 to 10:1 of Omega 6 to 3. But doesn’t that seem like a lot of Omega 6? Remember with the almost ubiquitous locations of omega 6, this ratio will be hard enough to find as it is! But yes this is the ratio that is recommended.

An excerpt from The Government’s Big Fish Story by Sabrina Rubin Erdely, “Changing agricultural techniques have worsened the situation. The natural omega-3 contents of meat, milk, and eggs have plummeted now that our livestock no longer graze on ALA-rich grass, instead consuming corn, wheat, and other grains that are loaded with another group of fatty acids, called omega-6s. In fact, the disappearance of omega-3s from our diets has coincided with an upsurge in omega-6s, mainly in the form of cereals, grains, and processed foods made with hydrogenated oils. Dr. Simopoulos estimates that in caveman days, we ate an equal amount of the two types, but that the average American now eats 16 times more omega-6s than omega-3.” A link is provided for this article, it is well worth reading.

Omega 3 FAs

Of the Omega 3s, there are 3 of them: α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA is found in nuts, seeds and plants.

ALA (α-linolenic acid)

We will see them in rapeseed (canola), soybeans, walnuts, flaxseed (Linseed), and others. It is also found in broad leaf greens. These greens are eaten by many animals and thus the animals that consume these greens, themselves become a source of ALA. It is important to note that the sources of ALA are often those that we also see as a source of n-6.

This n-3 may not be as great as its two siblings. While as noted above, its lack of feeding to livestock has helped make the search for a proper 6 to 3 ratio more difficult; it is not the FA we need to be necessarily reaching for. While it has been associated with lowering cardiovascular disease risk, it is not clear whether or not it is from ALA itself or the fact that the body can convert ALA to DHA and EPA. Can we just take ALA and avoid eating fish? No, sorry. The conversion of ALA to EPA is limited and too much ALA may actually inhibit EPA. Furthermore from wikipedia… “Some studies have linked α-linolenic acid with rapidly progressing prostate cancer[8] and macular degeneration,[9] increasing the risk 70% over control subjects (over those that did not receive α-linolenic acid).” Where end note 8 is: Brouwer IA, Katan MB, Zock PL (2004). "Dietary α-linolenic acid is associated with reduced risk of fatal coronary heart disease, but increased prostate cancer risk: a meta-analysis.". Journal of Nutrition 134 (4): 919–922. PMID 15051847. Retrieved on 13 November 2006. PMID 15051847 and end note 9 is: Eunyoung Cho, Shirley Hung, Walter C Willett, Donna Spiegelman, Eric B Rimm, Johanna M Seddon, Graham A Colditz and Susan E Hankinson (2001). "Prospective study of dietary fat and the risk of age-related macular degeneration". American Journal of Clinical Nutrition 73 (2): 209–218. PMID 11157315.Retrieved on 13 November 2006. PMID 11157315

So ALA is like n-6s in that we need them, but in moderation.

DHA (docosahexaenoic acid) and EPA (eicosapentanoic acid)

These are the n-3s that are obtained solely (no pun intended) from fish! The n-3s originate from photosynthetic and heterotrophic microalgae which are consumed by fish, which are often consumed by other fish. Ergo, any fish will do! Also as we get higher up the food chain, there is a higher concentration of the n-3 FAs! Great news for seafood lovers. (at the end of this lecture I have a weblink for seafood choices that are safe for the environment).
What is so great about DHA and EPA? To begin with virtually every cell requires them. The brain and eye especially need DHA. In fact, a neuron’s plasma membrane is made of about 50% of DHA! From the Government’s Big Fish Story, “While omega-3s reduce our body's inflammation response, omega-6s encourage it.” This means that DHA and EPA are where we see so many of the medical benefits with our dog and cat patients with inflammatory diseases such as skin allergies and arthritis.

Hill’s Science diet recognized the powerful benefits of EPA and formulated their joint diet called j/d. It contains 3374 mg of Omega 3 FAs per cup of j/d. The EPA levels are so concentrated that after two weeks of being on j/d many inflammatory mediators will stop being formed. In fact j/d is so concentrated in fish oils that a medium sized dog would need to eat 33 fish oil capsules every day in order to get the same amount of EPA as j/d! Hill’s took this diet to the FDA and asked them to test it by the same rigid requirements that they would for a new arthritis pain medication; and it passed! Also a few important points for those concerned about Science Diet Formulas: 1) there are absolutely NO artificial preservatives. J/D is preserved with tocopherol (from soy bean oil, and is a dietary sourced of Vitamin E), citric acid and rosemary extract. The fish source is menhaden fish (a cold water fish from the Chesapeake Bay, also known as a mossbunker or pogy). None of their fish have been treated with artificial preservatives and this included ethoxyquin! So as far as diets go: it is has the highest level of Omega 3 FA of any dog food available and has absolutely no preservatives. For those that don’t trust Science Diet – this may be an exception to consider or at least a reason to find a source of EPA for any pets with arthritis. Unfortunately there is not a feline J/D available at this time. Now moving on…

Beyond the vast area of reducing inflammation of skin, joint arthritis, immune mediated disease and other allergic disorders, DHA and EPA have been shown to be beneficial with the human diseases of Alzheimer’s disease and rheumatoid arthritis. Also in humans, DHA and EPA helps lower blood pressure, lower blood triglyceride levels, decrease risk of stroke, reduce the risk of breast, prostatic and colonic cancer, stimulate blood circulation, and help reduce depression. This is not even a complete list by any means. In other Hill’s Science Diet foods it is used in c/d to help reduce bladder inflammation and treat FLUTD as well as crystalluria, in k/d to promote increased kidney blood flow and health in renal failure cases, in b/d to help promote brain function and treat pets with CDS (Cognitive Dysfunction Syndrome), in h/d to improve cardiac health, in d/d to reduce dermal inflammation in pets suffering from atopy and other causes of dermatitis and also used in n/d to help cancer patients not only battle cancer but to help them deal with the chemotherapeutic agents that might be given to them. These are listed as examples of n-3 FA uses in veterinary medicine; there are any other diets such as Nutromax, Eukanuba, Blue Buffalo and many others which utilize the healing benefits of Omega 3 FAs.

To summarize, in veterinary medicine we can help promote the health of the brain, skin, heart, kidney, bladder, and joints as well as to help cancer patients. From extrapolation from human medicine, we think that they help promote a mental state of wellbeing and fight against depression. Pretty cool stuff these fish oils are.

What doses can we use if we are on another diet? According to Joe Bartges, DVM, PhD, DACVIM, DACVN from the University of Tennessee, “10-200 mg/kg/day”. There are various doses specifically for cancer, arthritis, etc which seem to fall on the higher end near 200 mg/kg/day. There are many forms of fish oils out there. One of my favorites is Derm Caps 3V Free Form Liquid by DVM products that focuses on a high Omega 3 Fatty Acid supplement in a convenient liquid pump which has a air tight bladder to preserve freshness.

“Just throw some olive oil on top of the food… or raw eggs…”

If you have read to this point, this statement which I hear from many people, unfortunately including some veterinarians should be apparently a foolish statement but let’s look into it a bit more anyways. Olive oil is made up primarily of a monounsaturated fatty acid called oleic acid. It is not an essential fatty acid, and nope, it doesn’t have any n-3s at all as it is from an olive and not a fish. In fact at high levels oleic acid and other monounsaturated fatty acids might be linked to an increase risk of breast cancer in humans: (Valeria Pala, Vittorio Krogh, Paola Muti, Véronique Chajès, Elio Riboli, Andrea Micheli, Mitra Saadatian, Sabina Sieri, Franco Berrino (2001). "Erythrocyte Membrane Fatty Acids and Subsequent Breast Cancer: a Prospective Italian Study". JNCL 93. PMID 11459870. Retrieved on 30 November 2008.)

As an unusual side note from Wikipedia, “Oleic acid is emitted by the decaying corpses of a number of insects, including bees and Pogonomyrmex ants and triggers the instincts of living workers to remove the dead bodies from the hive. If a live bee or ant is daubed with oleic acid, it is dragged off as if it were dead.”

Now with that said, I used some extra virgin olive oil to cook my dinner of Puttanesca tonight, which I might add was delicious. To note, this meal was apropos as it has anchovies in it. Thus it helps balance my Omega 6 to Omega 3’s and adds a little oleic acid for that wonderful Italian taste! So the point is not to stop using olive oil... just stop using to it help skin allergies and put it back where it belongs – in some wonderful cooking creation; then go and buy some fish oils for your pets.

So what does olive oil do for the pet? Not much for the skin. It might have a laxative effect, and bees might think your pet is not feeling so well.

What about eggs? Or vegetable oil for that matter? Remember these guys are sources of Omega 6. We are already getting our full share in the kibble. If you are giving eggs for taste or other reasons, go ahead but do not add it for help with skin allergies. It doesn’t; it makes it worse by increasing the Omega 6s in comparison to the Omega 3s and thus driving inflammation up. And vegetable oil? Let’s cut that out all together. Not only do we not want to increase skin inflammation but we don’t need a bout of pancreatitis either.

“Hey these capsules are great – they give me 3, 6 and 9!”

Ack… No more 6’s please! Many formulations in the grocery store, health food store and pet store have 3, 6 and sometimes 9 as combination formulas. Many of the human brands boast about it, as if it were more complete that the Omega 3 fish oil bottle sitting next to it. If you eat like most normal humans, we are already consuming far too much Omega 6s and most of us can make our own Omega 9s (again, it is not an EFA). Finally remember it is all about ratios. If we naturally eat n-6 FA, then take a supplement of 3 and 6 we are just wasting of time, money and the effort of swallowing pills.

In Summary

Thanks to those that have born with me on this journey of fatty acids without lapsing into a coma - or perhaps I should say… thanks to those that have regained consciousness and finished reading it. I hope this has taken an important subject and made it as simple as I can without jeopardizing the core information.

My goal here is neither to promote Hill’s Science Diet nor to have you stop eating certain foods. My goal here is to promote the use of Omega 3 Fish Oils and to have everyone think about reducing the omega 6 intake to maintain a proper ratio between Omega 6 and Omega 3 FAs. My second goal is to help dispel the myths of bottles promoting Omega 3,6,9 and the use of olive oil or other alternatives to fish oils. Fish oils are not very expensive and are well worth the money.

If there are any other topics that you might like a lecture on, please feel free to let me know.

Finally I have attached a copy of the picture of the Derm Caps 3V Free Form Liquid by DVM products. Please do NOT confuse this with the Derm Caps Liquid by DVM which is an excellent source of superfluous Omega 6. It needs to be the 3V Free Form. Nutromax also has a good one. I also have a link to the Government’s Big Fish Story which covers the benefits of fish oils with humans. There is also a link to the Monterey Bay Aquarium seafood watch for green seafood choices.

Thanks for the great info, Dr. Lee. And what the heck are you doing up at this hour? You'll be happy to know that your article did not put me to sleep. Although given that I have insomnia right now, I was kinda hoping it would.

Thanks for the information, Dr. Lee.
I have started feeding my dog sardines weekly, and just bought him some of the squirt-on fish oil, thinking it would help his skin. Now I feel more cofident that it's a good choice.

I do have a question for you though. I have heard that feeding salmon oil causes a dog's system to use up it's supply of vitamin E slowly making the dog deficient, and that vitamin E should be supplemented along with the salmon oil. Is this true? If so, how much vitamin E should be supplemented in comparison to the amount of salmon oil fed? I would also be interested to hear what you believe is a good amount of salmon oil to supplement with as the suggested 16-18 mL (for 85lb dog) on my bottle of salmon oil seems like a lot, no?